Door lock apparatus have been conventionally known, which includes a latch mechanism, a lift lever, an open lever, a lock operation lever and a link member. For example, US2004036298A1 discloses such type of door lock apparatus. In this door lock apparatus, the latch mechanism can be adjusted to a vehicle door and can be engaged with, and disengaged from, a striker of a vehicle body. The lift lever is configured to operate the latch mechanism from an engaged condition, in which the latch mechanism is engaged with the striker, to a disengaged condition. The lock operation lever is configured to move between an unlock position and a lock position in response to operation of a lock-unlock member of a vehicle door. The link member operates via the open lever in response to operation of a door handle of the vehicle door and is configured to move between an unlock position and a lock position in association with the lock operation lever. When the link member is at the unlock position, the link member can be engaged with the lift lever in response to the operation of the open lever and can operate the lift lever in a direction, which leads to disengagement of a latch of the latch mechanism from the striker. On the other hand, when the link member is at the lock position, the link member misses the lift lever; in other words, the link member is not engaged with the lift lever. In such circumstances, the latch of the latch mechanism is not disengaged from the striker.
According to this type of door lock apparatus, under the door lock condition, if an operation of the door handle and an operation of a lock-unlock member such as a lock knob are implemented at or about the same time, at least the following could occur. That is, when the operation of the door handle is implemented earlier than the operation of the lock-unlock member, the link member misses the lift lever. The link member is then moved in a direction of the unlock position from a position at which the link member missed the lift lever, in response to the operation of the lock-unlock member. In such cases, because the link member comes in contact with the lift lever from a side at which the link member can not operate the lift lever, a door unlocking operation is disabled. As a result, a door opening operation is disabled. Such a situation is referred to as “a state of panic”. Therefore, in order to switch a door condition from a door lock condition to the door unlock condition, it is necessary to carry out a door unlocking operation, after loosing the operation of the door handle and then shifting the link member to the position at which the link member can be engaged with the lift lever. Those operations, however, may on occasions appear unfavorable.
In order to solve such unfavorable operations, the door lock apparatus disclosed in JP2004-044360A includes the lock operation lever configured with an active lever, which is operatively associated with a lock-unlock member side, and a sub lever, which is provided so as to be movable relative to the active lever and is operatively associated with the link member side. The lock operation lever is further configured with a biasing member between the active lever and the sub lever.
According to the aforementioned configuration of the door lock apparatus, even if a panic state comes up due to the operation of the lock-unlock member that is implemented during the operation of the door handle, a relative movement of the sub lever and the active lever is still enabled. Even if the sub lever is at the panic state, the active lever can moved to the unlock position. In such conditions, in response to a return of the door handle, the engagement or contact between the link member and the lift lever is released, and the sub lever and the link member is shifted, by the biasing member, to the unlock position. As described above, even if a panic state comes up due to an operation of the lock-unlock member implemented at or about the same time as an operation of the door handle, it is possible to smoothly switch a door condition from the door lock condition to the door unlock condition.
According to the above-described conventional door lock apparatus, in order to assemble the lock operation lever to the door lock apparatus, it was necessary to build the active lever, the sub lever and the biasing member respectively relative to the door lock apparatus. More specifically, the active lever is first placed at a predetermined position relative to a base member of the door lock apparatus, and the biasing member is mounted on the active lever placed at the predetermined position. The sub lever is then mounted on the biasing member mounted on the active lever. Here, a connecting shaft of the sub lever extends through a bore of the active lever and a bore of the base member, and the lock operation lever is assembled to the door lock apparatus, while positions of the sub lever and the biasing member are supported relative to the active lever. However, an assembling process of the lock operation lever to the door lock apparatus remains complicated, in which an assembling efficiency goes down. Moreover, a manufacturing process of the door lock apparatus may become complicated.
The present invention has been made in view of the above circumstances, and provides a door lock apparatus used in a vehicle for example, in which respective members configuring a lock operation lever can be assembled to the door lock apparatus at an enhanced assembling efficiency, and a process of manufacturing the door lock apparatus can be simplified.